1. Field
The present disclosure relates to a fuel cell system and a fuel cell automobile.
2. Description of the Related Art
Fuel cell systems with loads driven by two power sources have hitherto been known. In a typical fuel cell system with a load driven by two power sources, a fuel-cell-side converter is provided between the load and an output terminal of a fuel cell and an electrical-storage-device-side converter is provided between the load and input-output terminals of an electrical storage device to drive the load. Such a fuel cell system with a load driven by two power sources is illustrated in, for example, FIG. 1 of Japanese Unexamined Patent Application Publication No. 2008-91319.
In a typical fuel cell system with a load driven by two power sources, as described in Japanese Unexamined Patent Application Publication No. 2008-91319, the fuel-cell-side converter is in a direct connection state and the fuel cell voltage is controlled by the electrical-storage-device-side converter in a low fuel cell power area where the fuel cell voltage is higher than the back electromotive force of the drive motor and the fuel cell output current is small (refer to [0043] in Japanese Unexamined Patent Application Publication No. 2008-91319). In contrast, the fuel-cell-side converter is in a step-up state and the fuel cell voltage is controlled by the fuel-cell-side converter in a high fuel cell power area where the fuel cell voltage is lower than the back electromotive force of the drive motor and the fuel cell output current is large (refer to [0044] and [0045] in Japanese Unexamined Patent Application Publication No. 2008-91319).